The present application relates to a traction apparatus that is used as a medical treatment device to hoist the neck or waist of a human body and a rope take-up mechanism of the traction apparatus.
The traction apparatus of FIGS. 5A and 5B shows a conventional mechanism used as a medical treatment machine that hoists the neck or the waist of a human body. FIG. 5A shows a schematic configuration of the traction apparatus. FIG. 5B shows the traction apparatus shown in FIG. 5A as viewed from the direction of arrow “a”.
In the conventional traction apparatus that is shown in FIG. 5A and FIG. 5B, a traction rope (also simply called a “rope”) 110 that hoists a neck or a waist of a human body in the direction of arrow “c” passes along a pulley C143, a pulley B142, a pulley D144, and a pulley A141 to be led to a take-up drum 111. The rotating surface of the pulley D144 is perpendicularly disposed with respect to the rotating surface of the other pulleys A, B, and C.
In this way, the conventional traction apparatus causes the load that acts on the traction rope 110 to be transmitted to a rope take-up mechanism that is intricately combined. The load in the direction of arrow “b” applied to the pulley D144 acts on a coil spring 145 that undergoes linear displacement. The coil spring 145 contracts in proportion to the load, and the displacement is detected as a voltage change of a potentiometer 146. Thereby, the load on the rope 110 is detected. The center shaft of the take-up drum 111 is joined to a spiral spring (spring) not shown. For that reason, a constant tension always acts on the rope 110, and a level position of the rope 110 is maintained as shown in FIG. 5A and FIG. 5B without sagging.
As described above, in the conventional traction apparatus, the rope 110 is bent a number of times by a plurality of pulleys.
In order for the rope take-up drum 111 to take up the rope 110 in an orderly manner, a winding groove 111a with a semi-circular shape of the cross-section of the rope is provided in the take-up surface. The rope 110 is taken up on the take-up drum 111 along this winding groove 111a. 
As a traction apparatus of this type, there has been proposed a sitting traction apparatus that is provided with a sling device for slinging up the underarms of a patient and a seat portion that has a fixture for fixing the thighs, and so by hoisting the seat portion (upper half of the patient's body) vertically, treats the lumbar and the like (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2003-88540).
As a conventional traction apparatus, there has been proposed a traction apparatus that has a load cell that detects traction force, and along with detecting traction force, is constituted so as to use the detection signal for drive control of a motor that is a drive source of traction force (for example, refer to Japanese Unexamined Patent Application, First Publication No. S59-118156).
The conventional traction apparatus described above causes the rope 110 to be bent a number of times by the plurality of pulleys. Also, this traction apparatus detects the load on the rope 110 using a coil spring 145 that is attached to the pulley 144. This results in a structure in which a load is placed on the rope 110. Also, the winding groove 111a with a semi-circular shape of the cross-section of the rope is provided in the take-up surface of the take-up drum 111 for the rope 110. The rope 110 is worn by the edge of this winding groove 111a, and the life of the rope is shortened. The wearing of the rope 110 leads to the surface of the rope being cut down, whereby rope scraps are generated. As a result of these scraps entering the moving portions of a mechanism, the problem arises of causing malfunction.